shadow value是什么意思？请问在经济学中，shadow value一般是如何应用的。期望版内大牛不吝赐教，越详细越好！
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文献标题：On the determinants of credit rationing: Firm-level evidence from transition countries
作者姓名：Drakos和Giannakopoulos
期刊来源：Journal of International Money and Finance 30 (2011) 1773–1790

原文摘录如下：
Asymmetry of information in the loan market may be ex ante, generated by the lender’s difficulty to
distinguish between ‘good’ and ‘bad’ borrowers when deciding which loan applications should be
granted, and/or ex post due to the lender’s imperfect and costly monitoring of borrower’s actions. Jaffee
and Russell (1976) and Stiglitz and Weiss (1981) demonstrate that when adverse selection and moral
hazard problems between borrowers and lenders remain unresolved, may lead to an equilibrium credit
rationing. Essentially, in such equilibrium there is excess demand for credit, and lenders find it optimal
to allocate credit by rationing, rather than charging a higher interest rate that would clear the market.
Due to adverse selection increasing the loan rate is sub-optimal, because it leads to a deterioration of
applicants’ pool and thereby reduces bank’s profits. Consequently, there is a demand segment for
which the shadow value of obtaining an extra dollar of loan would be higher, and therefore may even
be willing to pay above the prevailing interest rate but still denied access to credit. One of the most
important side effects of credit rationing is that a set of investment projects, even though exhibiting
a sufficiently positive Net Present Value, may not be funded on the basis of loan applicants’ characteristics
that are thought as signaling a ‘bad’ loan. The consequences of such an outcome may hinder
production, employment and business fixed investment and are especially intensified when the firm is
more reliant on external credit (Greenwald et al., 1984; Fazzari et al, 1988; Gertler, 1988; Hubbard,
1998; Bernanke and Gertler, 1990, 1995).

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